Substrate cleaning chamber and components

ABSTRACT

A substrate cleaning chamber comprises various components, such as for example, a consumable ceramic liner, substrate heating pedestal, and process kit. The consumable ceramic liner is provided for connecting a gas outlet channel of a remote gas energizer to a gas inlet channel of a substrate cleaning chamber. The substrate heating pedestal comprises an annular plate having a substrate receiving surface with a plurality of ceramic balls positioned in an array of recesses. A process kit comprises a top plate, top liner, gas distributor plate, bottom liner, and focus ring.

RELATED APPLICATION

This application is filed as a non-provisional application and claimspriority from provisional application No. 60/940,959 which was filed onMay 30, 2007, and which is incorporated by reference herein in itsentirety.

BACKGROUND

In the processing of substrates such as semiconductors and displays,layers are formed on the substrate, and then etched to form featuressuch as electrically conducting interconnects, contacts, vias, gates andbarriers. For example, a pattern of electrical interconnect lines can bemade by depositing a metal-containing conductor on the substrate,forming a patterned etch resistant material on the conductor, etchingthe conductor to form the interconnect lines, removing remnant resist,and depositing dielectric over the etched features. The dielectric layercan be further etched to form contact holes or vias that expose theunderlying metal-containing conductor material or other substratelayers. Electrically conducting material is then deposited into theetched holes or trenches to electrically contact the underlyingconductor. For example, in the formation of copper-containinginterconnects, the dielectric layer can be etched to form contact holesthat expose an underlying copper conductor material. A thin seed layerof copper can be deposited over the exposed conductor and contact holeto facilitate subsequent copper electroplating processes to fill thecontact holes.

However, contaminants and undesirable surface material on themetal-containing conductor require cleaning of the exposed conductorsurfaces before subsequent process steps are performed. For example, anative oxide film often forms on a conductor exposed to oxygen speciesduring an intermediate process step, for example, during a resiststripping process in which an oxygen-containing gas plasma is used tostrip resist, or when transferring the substrate between differentchambers. The oxide films increase the electrical resistance at thecontact interface between conductor surfaces. The surface material canalso have residual process deposits from previous processes, such as forexample carbon-containing, silicon-containing, fluorine-containing, andnitrogen-containing process residues. These process deposits can causevoids or other irregularities to form at the interface between theexposed and deposited materials.

Substrate cleaning chambers, also known as pre-clean chambers, are usedto clean oxide films and other undesirable process deposits from thesubstrate surface prior to processing and in between processing steps.During the cleaning process, the substrate is supported in the cleaningchamber and an energized cleaning gas is formed in a remote gas chamberand introduced into the chamber. The cleaning gas reacts with and removethe surface residues. In some processes, the substrate heating pedestalincludes a heating element to control the temperature of the substrateduring cleaning.

However, one problem with the use of an energized cleaning gas in suchcleaning processes is that it is difficult to control the energy of theradical and ionic species of the excited cleaning gas. Higher energycollisions between the cleaning gas and the substrate surface can causedamage to the underlying substrate. Lighter ions in the cleaning gas,such as for example H⁺ can also be detrimental when they penetrate thesurface of the substrate to damage underlying dielectric layers. Thus,it is desirable to control the energy of, and type of energized speciesintroduced into the process chamber.

Another problem is that the cleaning gas often etches away and erodesthe remote chamber wall 'surrounding the excitation region of the remotewithin a gas energizer, and can even etch and erode components insidethe cleaning chamber. Such erosion damages these components, and if thecomponent is an integral part of the chamber, the chamber must be shutdown to allow the component to be refurbished or replaced after apredetermined number of process cycles, which is undesirable.Conventional stainless steel walls and liners are particularlysusceptible to erosion and require frequent replacement orrefurbishment.

Yet another problem occurs when the substrate heating pedestal in thecleaning chamber that contacts the substrate, transfers contaminants andprocess residues deposits to the backside of the substrate or evenscratches the substrate during the substrate transferring process.Substrate heating pedestals containing heating elements can also providenon-uniform heating across the surface of the substrate. Substrateheating pedestals having a substrate receiving surface made up of raisedmesas and grooves allow flow of a heat transfer gas behind the substrateto improve temperature uniformity but still transfer undesirable amountsof process residues and deposits to the substrate.

Thus, it is desirable to have a cleaning chamber and gas energizer thatcan selectively filter energized gas species, for example, to filter outcertain ionic species from the cleaning gas. It is also desirable tohave chamber components that can be easily replaced or refurbished. Itis further desirable to have a substrate heating pedestal that minimizescontamination of the substrate by the transfer of process deposits tothe backside surface of the substrate. It is also desirable to have asubstrate heating pedestal that allows a more uniform heating of thesubstrate.

DRAWINGS

These features, aspects, and advantages of the present invention willbecome better understood with regard to the following description,appended claims, and accompanying drawings, which illustrate examples ofthe invention. However, it is to be understood that each of the featurescan be used in the invention in general, not merely in the context ofparticular drawings, and the invention includes any combination of thesefeatures, where:

FIG. 1 is a sectional side view of an embodiment of a substrateprocessing apparatus comprising a substrate cleaning chamber;

FIG. 2A is an exploded perspective view of a consumable ceramic linerbeing fitted into a top plate of the cleaning chamber using a linerlocking cylinder and liner holding tool;

FIG. 2B is a schematic side view of the ceramic liner and liner lockingcylinder fitted into the top plate of the cleaning chamber;

FIG. 3A is a perspective view of a substrate heating pedestal havingceramic balls embedded in the substrate receiving surface;

FIG. 3B is a cross sectional schematic view of the substrate heatingpedestal of FIG. 3A having first and second discs with a brazed bond,and an embedded heating element;

FIG. 4A is an exploded perspective view of a process kit and gasdistributor plate;

FIG. 4B is a schematic partial sectional view of the process kit, gasdistributor plate and substrate heating pedestal in a cleaning chamber;

FIG. 4C is a top view of the gas distributor plate; and

FIG. 5 is a schematic view of a substrate processing apparatuscomprising a substrate cleaning chamber.

DESCRIPTION

An embodiment of an substrate apparatus 20 comprising a cleaning chamber24 suitable for cleaning a substrate 22, is shown in its FIG. 1. Thecleaning chamber 24, as shown, is suitable for cleaning substrates 22such as semiconductor wafers; however, the cleaning chamber 24 can beadapted by those of ordinary skill to clean other substrates 22, such asflat panel displays, polymer panels, or other electrical circuitreceiving structures. Thus, the scope of the present invention shouldnot be limited to the illustrative embodiments of the cleaning chambershown herein. Generally, the cleaning chamber 24 comprises one or moreenclosure walls 30, which can include an upper wall 32, sidewalls 34,and a bottom wall 36, and which enclose a process zone 38. Energizedcleaning gas is provided to a gas inlet channel 40 of the cleaningchamber 24 from a remote chamber 42. The cleaning gas reacts with thesubstrate 22 and other surfaces within the chamber 24. Spent gas andbyproducts are exhausted from the chamber 24 through an exhaust system44 which may include an exhaust port 46 that receives gas from theprocess zone 38, and can also include a throttle valve 48 to control thepressure of gas in the chamber 24, and one or more exhaust pumps 50,such as a turbo-molecular exhaust pump. The exhaust system 44 can becapable of maintaining a sub-atmospheric pressure in the chamber 24.

A remote chamber 42 suitable for remotely energizing the cleaning gascomprises a remote gas energizer 52 which couples energy to a gasenergizer zone 54. A cleaning gas source 56 provides a cleaning gas tothe gas energizer zone 54. A flow valve 58 can be provided to control aflow rate of the cleaning gas into the remote chamber 42. The gasenergizer 52 couples energy to the cleaning gas in the gas energizerzone 54 to form an energized cleaning gas comprising ionic and radicalspecies. The gas energizer 52 can couple, for example, RF or microwaveenergy to the cleaning gas. In one version, the remote gas energizer 52comprises an inductor antenna 57 that inductively couples RF energy tothe cleaning gas in the gas energizer zone 54 at a power level of, forexample, from about 100 Watts to about 10 kWatts. The gas energizer 52can also be a toroidal gas energizer to couple energy to the cleaninggas in the remote zone 54, as for example described in U.S. Pat. No.6,150,628 to Smith et al., which is incorporated by reference herein andin its entirety. A suitable RF power level applied by the toroidal gasenergizer may be from about 1000 Watts to about 10,000 Watts. A remotegas energizer 52 comprising a microwave gas activator providing amicrowave power level of from about 300 Watts to about 5 kW, can also beused.

A consumable ceramic liner 60 connects a gas outlet channel 62 of theremote gas energizer 52 to a gas inlet channel 40 of the chamber 24, asshown in FIGS. 2A and 2B. The liner 60 serves to protect the channels40, 62 by covering their inner surfaces with at least a portion of thesurface of the liner 60, such that the inner surface 61 of the liner 60is exposed to the energized gas species. The liner 60 comprises an inletcylinder 64 having an outer diameter sized to fit in the gas outletchannel 62 of the remote gas energizer. In one version, the inletcylinder 64 has a length L that is sufficiently long to extend out fromthe remote chamber 42 by a distance of at least about 50 mm. The lengthL is sufficiently short to terminate at least about 1 mm before the endof the gas inlet 40 of the chamber 24. In one version, the inletcylinder 64 has a length L of from about 100 to about 110 mm, and adiameter of between about 1 cm to about 4 cm.

A conical flare 66 joins the inlet cylinder 64 to an outlet cylinder 68.The conical flare 66 comprises a tube having a diameter that increasesalong a conical surface over the length of the flare 66. The conicalflare 66 has an upper end 70 and a lower end 72. The outer diameter ofthe upper end 70 of the conical flare 66 is sized to correspond to theouter diameter of the inlet cylinder 64 at the junction between theconical flare 66 and the inlet cylinder 64. The outer diameter of thelower end 72 of the conical flare 66 is sized to correspond to the outerdiameter of the outlet cylinder 68 at the junction between the conicalflare 66 and the outlet cylinder 68. The diameter of the lower end 72 ofthe conical flare 66 is larger than the diameter of the upper end 70 ofthe conical flare 66 by at least a factor of 1.5. In one version theinlet cylinder 64, the conical flare 66 and the outlet cylinder 68 areintegrally connected.

The conical flare 66 serves to gradually increase the diameter of theinner volume of the liner 60 between the upper and lower ends 70, 72 toprovide a more uniform distribution of energized gas species enteringthe process chamber. An abrupt change in diameter was believed to resultin non-uniform gas distribution from the outlet of the liner. Theconical flare 66 gradually tapers the diameter from the first diameterof the inlet cylinder 64 to the second diameter of the outlet cylinder68 to provide a gradual increase in volume along the flow path of thedissociated gas species. In one version, the conical flare 66 comprisesa conical surface that is angled relative to a vertical axis passingthrough the centerline of the conical flare, at an angle of from about10 degrees to about 60 degrees. Also, the ratio of the length of theconical flare 66 to the length of the outlet cylinder 68 is from about1:2 to about 1.8. Spacing the increase in volume across a length of theconical flare 66 provides better distribution of gas species at theoutlet end 72 of the conical flare 66.

The liner 60 also has an outlet cylinder 68 that is connected to the gasinlet channel 40 of the substrate cleaning chamber 24. In one version,the outlet cylinder 68 has an outer diameter sized to fit in the gasinlet channel 40 of the substrate cleaning chamber 24. The outletcylinder 68 has a length L that is sufficiently short to terminatebefore a process zone of the cleaning chamber 24 to avoid erosion in thechamber environment. When the inlet cylinder 64 has a first diameter,the outlet cylinder 68 comprises a second diameter that is at least 1.5times larger that the first diameter. In one version, the outletcylinder 68 has a diameter of from about 2 cm to about 8 cm or moretypically about 4 cm. The outlet cylinder 68 protects the inner surfacesof the gas inlet 40 of the chamber from erosion by the energized gasspecies, while also increasing the diameter of the liner to reducecollisions between the energized gas species formed in the remote zone54.

The consumable liner 60 comprises a ceramic material capable ofscavenging an ion species from the energized gas generated in the remotegas energizer. For example, the liner 60 can comprise quartz, aluminumoxide or aluminum nitride. In one version, the liner 60 comprises quartzand is capable of scavenging hydrogen ions from the energized gas byadsorbing some of the hydrogen ions onto its inner surface 74. Thequartz inner surface 74 is believed to act as an ion filter 76 to reducethe recombination of the radicals by providing a surface to whichhydrogen-containing species can adsorb. It is also believed thathydrogen-containing species that impinge on the quartz surface 74release an adsorbed hydrogen-containing radical into the energized gasthereby regenerating free hydrogen radicals. However, hydrogen ions arenot regenerated by the quartz surfaces 74, and thus, the hydrogen ionsimpinging on the quartz surface recombine to form electrically neutral,non-ionic species. Thus, passing the activated or energized cleaning gasover the quartz surface 74, causes ionic species to be filtered out fromthe energized cleaning gas while hydrogen radicals are preserved.

The thickness of the consumable liner 60 is selected depending upon thenumber of process cycles the liner must withstand before replacement.The energized gas is capable of etching and eroding the liner 60, thus,the liner 60 must be replaced after a predetermined number of processcycles. Also, the adsorption properties of the liner 60 degrade as moreand more ions are adsorbed onto the surface of the ceramic liner. Thenumber of cycles that the liner 60 can withstand is related to thethickness of the liner 60. In one version, the liner 60 is sufficientlythick to scavenge ion species for at least about 30,000 process cycles,and has a thickness of from about 2 mm to about 6 mm.

The liner 60 can be made by molding a ceramic powder into the desiredshape, for example, by cold isostatic pressing. For example, ceramicpowder is combined with a liquid binding agent such as the organicbinding agent polyvinyl alcohol. The mixture is placed in a rubber bagof an isostatic pressing device and a pressure is uniformly applied onthe walls of the bag to compact the mixture to form a ceramic structurehaving the desired tubular shape. The pressure can be applied, forexample, by immersing the flexible container in water or by otherpressurizing methods. The molded ceramic preform can be made cylindricalor ring-like using a hollow tube mold, and the resultant molded ceramicpreform can be further shaped by machining. The shaped ceramic preformis then sintered to form a sintered ceramic. For example, aluminum oxidecan be sintered at a temperature of from about 1300° C. to about 1800°C. for about 48 to about 96 hours, typically at a pressure of about 1atm. The sintered ceramic material can be further shaped, for example,by machining, polishing, laser drilling, or using other methods, toprovide the desired ceramic structure.

The liner 60 is held in place in the chamber by a liner locking cylinder71. The liner locking cylinder 71 is sized to slide over the outerdiameter of the outlet cylinder 68 of the liner 60 and it rests againstan annular lip 69 of the outlet cylinder 68. as shown in FIGS. 2A and2B. The liner locking cylinder 71 fits in between the outer cylinder 68of the liner 60 and the aperture wall 73 to form a gas tight seal asshown in FIG. 1, and can b made from a metal or ceramic material.

Advantageously, the liner locking cylinder 71 facilitates placement intothe upper chamber wall 32, and also facilitates removal of the liner 60after it is exposed to plasma for a preset number of process cycles, forrefurbishment or replacement. The liner locking cylinder 71 comprises acircular flange 73 which extends out from one end of the lockingcylinder 71. The circular flange 73 has a flat key 75 which is insertedinto a matching flat key portion 77 on an annular lip 79 extending outfrom the upper chamber wall 32, as shown in FIG. 2B. Twisting the linerlocking cylinder 71 rotates the circular flange 73 so that it slidesbehind the annular lip 79 of the upper chamber wall 32 to lock thecircular flange behind the same. A locking blocker (not shown) such as alocking pin can be inserted into the pathway of the rotating circularflange 73 to block and stop the flange from further rotation.

A method of inserting the liner 60 into a chamber lid for connecting agas outlet channel 62 of a remote chamber 42 to a gas inlet channel 40of a cleaning chamber 24 is also demonstrated in FIG. 2B. In thismethod, the liner locking cylinder 71 is first placed over the outletcylinder 68 of the ceramic liner 60. Then, a liner holding tool 81 ispassed into the outlet cylinder 68 of the ceramic liner 60 so that theouter diameter of the liner holding tool 81 grips the inner diameter ofthe outlet cylinder 68. A user grasps the liner holding tool 81 and theninserts the inlet cylinder 64 of the ceramic liner 60 into the gasoutlet channel 62 of the remote chamber 42. The liner holding tool 81 isthen twisted to lock the circular flange 73 of the liner lockingcylinder 71 into a matching annular lip 79 of the upper chamber wall 32as described.

The chamber 24 may also optionally comprise a chamber gas energizer (notshown) that couples energy to the gas in the process zone 38 of thechamber 24. For example, the chamber gas energizer can comprise one ormore of electrodes and an inductor antenna to couple RF energy.

A substrate heating pedestal 80 is provided to hold the substrate 22 inthe process zone 38 of the substrate cleaning chamber 24 as shown inFIGS. 1, 3A, 3B and 4B. The pedestal 80 comprises an annular plate 82having a substrate receiving surface 84 with an array of recesses 88 anda heating element 92 embedded in the annular plate 82. The heatingelement 92 is controlled by a controller 78. The controller 78 is ableto supply a variable power level to the heating element 92 in responseto at least one of: input from one or more detectors 106 that monitorthe conditions in the cleaning chamber 24 or the remote chamber 42, orinput from a user of the apparatus 20. The pedestal 80 can optionallycomprise an electrode (not shown) that can be electrically biased tohold the substrate 22 to the pedestal 80 or affect the characteristicsof the process, such as the degree of ion bombardment of the substrate22. The bias applied to the electrode is also controlled by thecontroller 78.

A plurality of ceramic balls 90 are each positioned in a recess 88 onthe substrate receiving surface 84 as shown in FIG. 3A. The ceramicballs 90 are embedded in the surface 84 of the pedestal 80 such that aportion of the surface of each ball 90 is situated above the plane ofthe pedestal surface 84. As such, a top region 144 of the balls 90 makeup a raised substrate receiving surface 86 consisting of N discreteregions, where N is the number of balls 90 embedded in the surface 84 ofthe pedestal 80. The raised substrate receiving surface 86 is verticallyseparated from the pedestal surface 84. That is, the raised substratereceiving surface 86 is higher than the surface of the annular plate 82by from about 0.01 mm to about 0.5 mm. Supporting the substrate 22 by aseries of discrete points, and at a vertical distance from the surfaceof the annular plate 82 of the heating pedestal 80 allows for gas in thechamber 24 to transfer heat between the substrate 22 and the surface ofthe annular plate 82 during heating. Suspension of the substrate 22above the surface of the annular plate 82 allows for a more uniformheating of the substrate 22, as compared to contacting the substrate 22to the surface of the annular plate 82, because the thermal contact isnot directly affected by local variations in the thermal conductivityand surface contact characteristics of the plate 82.

In one version, the ceramic balls 90 are spherical in shape and thediameter of the balls 90 is sufficiently high to maintain the substratereceiving surface higher than the top surface of the annular plate byfrom about 0.01 mm to about 0.5 mm. Typically, the balls 90 comprise adiameter of between about 1 mm and about 3 mm. In one version, thespherical bodies have a diameter of about 2 mm and protrude from theupper surface of the annular plate 82 by about 0.04 mm. The ceramicballs 90 comprise at least one of silicon nitride, zirconium oxide,sapphire, synthetic corundum, and alumina oxide and in one versioncomprise alumina oxide.

The annular plate 82 is constructed from two disks 94, 96 which arebonded together with a brazed bond. In one version, as shown in FIGS. 3Aand 3B, the annular plate 82 comprises a first disk 94 having the raisedsubstrate receiving surface 86. The first disk 94 comprises a thicknessof from about 10 mm to about 30 mm and diameter of from about 10 cm toabout 70 cm. The diameter of the disk 94 is dependant on the dimensionsof the substrate to be processed. The receiving surface of the disk 94comprises a plurality of recesses 88 each having a diameter and a depthsufficient to receive a ceramic ball 90. The recesses 88 can be formedby machining and preferably comprise sides which are sloped inward bybetween about 2 and about 20 degrees such that the diameter of therecess 88 at the surface of the first disk is slightly less than thediameter of the ceramic ball 90. Recesses 88 machined in this manner arecapable of confining the inserted ceramic balls 90 to the surface of theannular plate 82 after insertion.

A second disk 96 is provided having a diameter to match the diameter ofthe first disk 94 and a thickness of between about 6 mm and about 15 mm.The second disk 96 comprises a channel 98 shaped to receive the heatingelement 92 and is made of at least one of aluminum, copper, titanium,molybdenum or stainless steel, or combinations thereof. In one version,the second disk comprises aluminum, and the brazing bond materialcomprises an aluminum brazing material. The heating element 92 comprisesa resistor assembly having sufficient electrical resistance to maintainthe surface 84 of the annular plate 82 at temperatures of from aboutroom temperature to about 400° C. The heating element 92 is powered viaterminal posts 100 which extend through the second disk 96 about thecenter 102 of the disk.

The annular plate 82 with embedded heating element 92 may be formed bymachining a first disk 94 from an aluminum sheet having a thickness ofabout 5 mm. Recesses 88 having a depth of about 2 mm from the surface 84of the first disk 94 are drilled into the surface 84 of the disk 94corresponding to the desired placement of the countersunk ceramic balls90. A second disk 96 is machined to have the same diameter as the firstdisk 94 from an aluminum sheet having a thickness of from about 11.5 mmto about 12.5 mm. A serpentine channel 98 is machined in the disk 96,the channel 98 having a width and depth corresponding to the dimensionsof the heating element 92. At least one pair of holes (not shown) aredrilled about the center 102 of the second disk 96. The drilled holeshave a diameter of at least 10% greater than the diameter of theterminals 100 of the heating element 92. The heating element 92 isapplied to the grooved side of the second disk 96 by pressing it intothe channel 98 and threading the terminals 100 through the drilledholes. A brazing foil or brazing compound is placed onto the groovedsurface of the second disk 96 such that it covers the surface of thesecond disk 96. The non-pitted side of the first disk 94 is held ontothe brazing surface and the assembly is aligned such that thecircumferences of the first and second disks 94, 96 overlap with eachother. The assembly is bonded together by placing the assembly in afurnace, heating the assembly to above the melting point of the brazingmaterial and applying pressure, such as in a hot press. The assembly isthen cooled to form a brazed bond 104.

The backside surface of the annular plate 82 is mounted to a supportpost 110 used for supporting the annular plate 82. The support post 110comprises a rod having a receiving surface adapted to receive thebackside surface of the annular plate 82. The rod may comprise a metalsuch as stainless steel or aluminum and may be a solid or a hollowstructure. In one version, the support post 110 also comprises a bellowsand a lift mechanism (not shown) that is adapted to raise and lower thepedestal 80 into position for receiving a substrate 22, treating thesubstrate 22 and removing the substrate 22 from the chamber 24. Themethod of fastening the annular plate 82 to the support post 110 cancomprise welding the support post 110 to the bottom surface of theannular plate 82, welding a threaded adapter to the bottom surface ofthe annular plate 82 and then screwing the annular plate 82 to thesupport post 110 or by welding a hollowed tube onto the bottom surfaceof the annular plate 82 and then clamping the hollowed tube to thesupport post 110.

A process kit 114 comprising several components 112 is provided tocontain the energized gas into the cleaning chamber 24 and distributethe gas across the substrate surface as shown in FIG. 4A and 4B. Thecomponents 112 of the process kit 114 can include, for example, a topplate 116, a top liner 118, a gas distributor plate 120, a bottom liner122, and a focus ring 124. The components 112 of the process kit 114 canbe easily removed from the chamber 24, for example, to replace or repaireroded components, or to adapt the cleaning chamber 24 for processingsubstrates 22 of different sizes. The process kit 114 components can bemade from quartz because quartz is effective at reducing therecombination rate of process gas radicals such as hydrogen radicals.

The top plate 116 comprises an annular disk 126 having an outerperipheral edge 128 and an orifice 130 for passing process gastherethrough as illustrated in FIG. 4A. The top plate 116 is sized tofit into the substrate cleaning chamber 24 and the orifice 130 has adiameter of between about 40 mm and about 45 mm and is located about thecenter of the top plate 116 such that the orifice 130 substantiallyoverlaps with the gas inlet channel 40 of the upper chamber wall 32. Thetop plate 116 contacts the upper wall 32 of the chamber 24. The topplate 116 contacts and is supported by the top liner 118. The top plate116 comprises a thickness of from about 1 mm to about 10 mm.

The top liner 118 contacts the outer peripheral edge 128 of the topplate 116. The top liner 118 comprises a cylinder that serves to confinethe energized process gas and to protect the walls 30 of the cleaningchamber 24 from the energized process gas. The liner 118 comprises athickness of from about 0.60 cm to about 0.70 cm. In one version, theouter peripheral edge 128 of the top plate 116 rests on the upper edge132 of the top liner 118.

A gas distributor plate 120 has a top surface 134 contacting the topliner 118, a bottom surface 136, and a plurality of holes 140therethrough for distributing process gas in the chamber 24. The holes140 are shaped, sized, and distributed in a spaced apart relationshipacross the surface of the plate 120 to promote uniform delivery of theprocess gas to the surface of the substrate 22. In one version, theplurality of holes 140 comprises four rings 139 a-d of holes 140 a-dthat are each sized with different diameters as shown in FIG. 4C. In oneversion, the innermost first ring 139 a of first holes 140 a that aresized with a diameter d. A second ring 139 b of second holes 140 b thateach have a diameter 2 d, are located radially outward of the first ring139 a. A third ring 139 c of third holes 140 c that each have a diameter3 d are radially outward of the second ring 139 b. A fourth ring 139 dof fourth holes 140 d that each have a diameter 4 d are being radiallyoutward of the third ring 139 c. Such a distribution of holes 140 a-dprovides more uniform delivery of the process gas to the surface of thesubstrate 22. In one version, the first holes 140 a have a diameter dwhich is from about 1 to about 5 mm, and the other holes 140 b-d aresized accordingly. As one example, the first ring of holes 140 a eachhave a diameter of from about 1 to about 5 mm; the second ring of holes140 b each have a diameter of from about 2 to about 10 mm; the thirdring of holes 140 c each have a diameter of from about 3 to about 15 mm;and the fourth ring of holes 140 a each have a diameter of from about 4to about 20 mm. In one version, the different diameter holes 140 a-d arealso spaced apart to include a larger number of holes on the fourth ring139 d, and progressive smaller numbers of holes for the third ring 139c, second ring 139 b, and first ring 139 a. The gas distributor plate120 can be composed of a ceramic, such as for example, aluminum oxide orsilicon oxide, and the silicon oxide can be quartz.

A bottom liner 122 contacts the bottom surface 136 of the gasdistributor plate 120 as shown in FIGS. 4A and 4B. The bottom liner 122also comprises a cylinder having an annular peripheral edge 142 thatextends outward from the cylinder. The peripheral edge 142 contacts thebottom surface 136 of the gas distributor plate 120 and the sidewall 34of the cleaning chamber 24.

A focus ring 124 is provided to focus the energized process gas onto thesubstrate 22. The focus ring 124 comprises an inner flange 148 whichrests on the peripheral edge of the support pedestal 80 and which has asloped upper surface 150 joining a vertical surface 151 at the substrateperiphery, as shown in FIGS. 3B and 4B. The sloped upper surface 150comprises an angle of between about 85 to about 100°, for example about95°. The focus ring 124 also has a foot 152 which is elevated about aouter ledge 154 of the substrate heating pedestal 80.

The process kit 114 components described above can comprise a filteringmaterial, such as for example quartz, to adsorb ionic species from theenergized gas to filter out the ionic species from the energized gas. Inone version, at least a portion of the surfaces of the top plate 116,top liner 118, gas distributor plate 120, bottom liner 122 and focusring 124 comprises quartz, for example a coating of quartz. The quartzcan be deposited onto the surfaces of these process kit 114 componentsby physical vapor deposition or by hydrothermal deposition. A suitablethickness for a layer of quartz on these surfaces is from about 0.01 mmto about 4 mm. In one version, the process kit 114 components 112 arecomposed of quartz.

The quartz surfaces 74 can be arranged to provide optimal filtering ofthe hydrogen ion species from the energized cleaning gas. In oneversion, the quartz surfaces 74 comprise the interior surface of aportion of the ceramic liner 60 that connects the gas energizer zone 54and the cleaning chamber 24. For example, the ceramic liner 60 cancomprise a quartz tube. In another version, the quartz surface 74comprises one or more surfaces of a gas distributor, such as for examplethe upper surface of the gas distributor plate 120. The quartz surfacesmay also comprise a wire grid situated between the remote zone and thesubstrate, for example above the process zone, to further filter theactivated cleaning gas.

In one cleaning process performed in the cleaning chamber 24 ofapparatus 20, the temperature of the substrate 22 is set to provideoptimum conditions for the reduction of oxides in the deposits, and caneven be set to accelerate the chemical reaction between thehydrogen-containing radicals and the deposits. For example, thetemperature of the substrate 22 may be maintained at from about 0 toabout 500° C., such as from about 150° C. to about 450° C., and evenfrom about 25° C. to about 350° C., such as from about 150° C. to about350° C. In one version, a bias power level applied to the substrate 22during the cleaning process may be desirably low, as a high bias powerlevel can increase the bombardment of the substrate 22 by ions in theenergized cleaning gas. A suitable bias power level may be less thanabout 100 Watts such as, for example, from about to about 0 to about 10Watts, and even from about 1 to about 10 Watts, and may even besubstantially zero. In another version, a higher bias power level may beapplied to increase the rate of cleaning, such as a bias power level ofgreater than 100 Watts, and even from about 100 Watts to about 200Watts.

It has further been discovered that cleaning of the substrate 22 can beimproved by performing a heat treatment or annealing step to removedeposits from the substrate 22. In the heat treatment step, thesubstrate 22 is heated to a temperature that is sufficiently high tovaporize material from the substrate 22. A flow of a reducing gas mayalso be provided during the heat treatment step to inhibit the formationof oxides on the substrate 22. A suitable reducing gas may comprise ahydrogen-containing gas, such as for example H₂. The heat treatment stepcan be performed without substantially energizing the reducing gas, forexample without substantially coupling RF or microwave energy to thereducing gas, to provide a relatively gentle initial clean of thesubstrate 22 prior to the energized hydrogen radical cleaning step.

In one version of a suitable cleaning process, a cleaning gas comprisingfrom about 50 to about 1000 sccm of H₂, such as 300 sccm of H₂, and fromabout 0 to about 10 sccm H₂O, such as 3 sccm H₂O is activated in thechamber 42 of the remote gas energizer 52 by applying a power level offrom about 300 Watts to about 3000 Watts, such as 1050 Watts. The remotechamber 42 pressure is maintained at less than about 10 Torr, such asabout 1 Torr. A bias power level of from about 0 to about 100 Watts,such as 50 Watts is applied to bias the substrate 22, and thetemperature of the substrate 22 is maintained at from about 150 to about450° C., such as 250° C. The cleaning process substantially removes thedeposits to provide a cleaned surface.

After the cleaning process has been completed, the pressure in thechamber 24 is reduced to a pressure of less than about 10 mTorr, toevacuate spent cleaning gas and cleaning by-products and to reduce thelikelihood of contamination of the multi-chamber apparatus 26 by thecleaning chamber 24. The substrate 22 can then be transferred undervacuum via a substrate transfer chamber having a transfer robot 119 to adeposition chamber 24 b to deposit a second metal-containing conductor21, such as at least one of copper, aluminum, tantalum, tungsten,tantalum nitride and tungsten nitride, on the freshly cleanedmetal-containing conductor surface.

A multi-chamber apparatus 20 suitable for processing substrates 22comprises one or more process chambers 28 a-d which can include thecleaning chamber 24, as shown in FIG. 5. The chambers are mounted on aplatform that provides electrical, plumbing, and other supportfunctions. The platform typically supports a load lock 156 to receive acassette 158 of substrates 22 to be processed and a substrate transferchamber 154 containing a robot 162 to transfer substrates 22 from thecassette 158 to the different chambers 28 a-d for processing and returnthem after processing. The different chambers 28 a-d may include, forexample, a cleaning chamber 24, a deposition chamber 28 b for depositingmaterials on wafers, optionally, a heat treatment chamber 28 c, andother processing chambers. For example, in one version, one of thechambers comprises the cleaning chamber 24 for removing deposits formedon a metal-containing conductor on the substrate 22. After the cleaningprocess is finished, the substrate 22 can be transferred by the robot162 to a deposition chamber 28 d to deposit material such as ametal-containing conductor on the cleaned substrate 22. The substrate 22can also be transferred by the robot 162 to a second deposition chamber28 c capable of depositing another material, such as anothermetal-containing conductor, over the first material deposited in thefirst chamber 28 b. The chambers 28 a-d are interconnected to form acontinuous vacuum environment within the walls 164 of the substratetransfer chamber 154 to provide as process which may proceeduninterrupted and reducing contamination of substrates 22. The transferchamber 154 comprises a wall 160 having an exhaust port 164 to exhaustgases and to maintain a low pressure environment, such as a pressure ofless than about 10 mTorr, in order to reduce contamination of thechambers.

The multi-chamber apparatus 26 can be operated by a controller 170 via ahardware interface. The controller 170 comprises a computer (not shown)having a central processor unit (CPU) that is coupled to a memory andperipheral computer components. Preferably, the memory may include aremovable storage media, such as for example a CD or floppy drive, anon-removable storage media, such as for example a hard drive, andrandom access memory. The controller 170 may further comprise aplurality of interface cards including, for example, analog and digitalinput and output boards, interface boards, and motor controller boards.In one version, the controller 170 comprises a computer-readable programmay be stored in the memory, for example on the non-removable storagemedia or on the removable storage media. The computer readable programgenerally comprises process control software comprising program code tooperate the chambers 28 a-d and their components, the transfer chamber154 and robot 162, process monitoring software to monitor the processesbeing performed in the chambers, safety systems software, and othercontrol software, as for example. The computer-readable program may bewritten in any conventional computer-readable programming language.

Although exemplary embodiments of the present invention are shown anddescribed, those of ordinary skill in the art may devise otherembodiments which incorporate the present invention, and which are alsowithin the scope of the present invention. For example, the chamber 24may comprise components other than those specifically described, aswould be apparent to those of ordinary skill in the art. Furthermore,the terms below, above, bottom, top, up, down, first and second andother relative or positional terms are shown with respect to theexemplary embodiments in the figures and are interchangeable. Therefore,the appended claims should not be limited to the descriptions of thepreferred versions, materials, or spatial arrangements described hereinto illustrate the invention.

1. A consumable ceramic liner for connecting a gas outlet channel of aremote chamber to a gas inlet channel of a substrate cleaning chamber,the ceramic liner comprising: (a) an inlet cylinder having an outerdiameter sized to fit in the gas outlet channel of the remote chamber;(b) an outlet cylinder connected to the gas inlet channel of thesubstrate cleaning chamber; and (c) a conical flare joining the inletcylinder to the outlet cylinder.
 2. A liner according to claim 1 whereinthe conical flare comprises a conical surface that is inclined from avertical axis at an angle of from 10 to about 60 degrees.
 3. A lineraccording to claim 1 wherein the ratio of the length of the conicalflare to the length of the outlet cylinder is from about 1:2 to about1:8.
 4. A liner according to claim 1 wherein the inlet cylindercomprises a first diameter and the outlet cylinder comprises a seconddiameter that is at least 1.5 times larger that the first diameter.
 5. Aliner according to claim 4 wherein the first diameter is from about 1 toabout 4 cm.
 6. A liner according to claim 4 wherein the second diameteris from about 2 to about 8 cm.
 7. A liner according to claim 1comprising a ceramic material capable of scavenging an ion species fromthe energized gas generated in the remote gas energizer.
 8. A lineraccording to claim 1 composed of quartz, aluminum oxide or aluminumnitride.
 9. A liner according to claim 8 wherein the liner comprises athickness of from about 2 mm to about 6 mm.
 10. A liner according toclaim 1 further comprising a liner locking cylinder that is sized to fitaround the outer diameter of the outlet cylinder.
 11. A method ofinserting a ceramic liner into a upper chamber wall for connecting a gasoutlet channel of a remote chamber to a gas inlet channel of a substratecleaning chamber, the ceramic liner comprising an inlet cylinder sizedto fit in the gas outlet channel of the remote chamber, an outletcylinder connected to the gas inlet channel of the substrate cleaningchamber, and a conical flare joining the inlet to the outlet cylinder,the method comprising: (a) placing a liner locking cylinder over theoutlet cylinder of the ceramic liner; (b) sliding a liner holding toolinto the outlet cylinder of the ceramic liner, the outer diameter of theliner holding tool being sized to grip the inner diameter of the outletcylinder; and (c) grasping the liner holding tool and inserting theinlet cylinder of the ceramic liner into the gas outlet channel of theremote chamber.
 12. A method according to claim 11 further comprising:(d) twisting the liner holding tool to lock an annular flange of thelocking cylinder into a matching annular lip of the upper chamber wall.13. A substrate heating pedestal for a substrate cleaning chamber, thesubstrate heating pedestal comprising: (a) an annular plate comprising afirst disk having a substrate receiving surface with an array ofrecesses, a second disk having a channel shaped to receive the heatingelement, and a brazed bond joining the first and second disks; (b) aplurality of ceramic balls that are each positioned in a recess on thesubstrate receiving surface; and (c) a heating element embedded in theannular plate.
 14. A pedestal according to claim 13 wherein the brazedbond comprises an aluminum brazing compound.
 15. A pedestal according toclaim 13 wherein the first and second disks comprise aluminum.
 16. Apedestal according to claim 13 wherein the ceramic balls are composed ofalumina oxide, quartz, sapphire, silicon nitride, synthetic corundum,zirconium oxide, or mixtures thereof.
 17. A pedestal according to claim13 wherein the ceramic balls comprise Al₂O₃.
 18. A pedestal according toclaim 13 wherein ceramic balls comprise a diameter of from about 1 toabout 3 mm.
 19. A pedestal according to claim 18 wherein the diameter ofthe quartz balls is sufficiently large to maintain the substratereceiving surface higher than the top surface of the annular plate byfrom about 0.01 mm to about 0.5 mm
 20. A gas distributor plate for asubstrate process chamber, the gas distributor plate comprising: (a) anfirst ring of first holes that each have a diameter d; (b) a second ringof second holes that each have a diameter 2 d, the second ring beingradially outward of the first ring; (c) a third ring of third holes thateach have a diameter 3 d, the third ring being radially outward of thesecond ring; and (d) a fourth ring of fourth holes that each have adiameter 4 d, the fourth ring being radially outward of the third ring.21. A gas distributor plate according to claim 21 wherein the diameter dis from about 1 to about 5 mm.
 22. A gas distributor plate according toclaim 21 wherein the second holes have a diameter of from about 2 toabout 10 mm.
 23. A gas distributor plate according to claim 21 whereinthe third holes have a diameter of from about 3 to about 15 mm.
 24. Agas distributor plate according to claim 21 wherein the fourth holeshave a diameter of from about 4 to about 20 mm.
 25. A gas distributorplate according to claim 21 composed of a ceramic.
 26. A gas distributorplate according to claim 21 wherein the ceramic comprises aluminum oxideor silicon oxide.
 27. A process kit for a substrate cleaning chamberhaving a chamber lid holding a gas distributor plate which faces asubstrate heating pedestal, the process kit comprising: (a) a top platefor contacting the chamber lid, the quartz top plate having an orificefor passing process gas therethrough, and having a perimeter edge; (b) atop liner contacting the perimeter edge of the quartz top plate andbeing above the gas distributor plate; (c) a bottom liner below the gasdistributor plate; and (d) a focus ring resting on a peripheral edge ofthe substrate heating pedestal.
 28. A process kit according to claim 27wherein a top plate, top liner bottom liner, and focus ring, allcomprise quartz.
 29. A process kit according to claim 27 wherein the topplate comprises an annular disk having an outer peripheral edge and anorifice for passing process gas therethrough.
 30. A process kitaccording to claim 27 wherein the top plate comprises a thickness offrom about 1 mm to about 5 mm.
 31. A process kit according to claim 27wherein the top and bottom liners comprise cylinders.
 32. A process kitaccording to claim 27 wherein the focus ring comprises an inner flangewhich rests on the peripheral edge of the substrate heating pedestal,the flange comprising a sloped upper surface that joins to a verticalsurface at the substrate periphery.
 33. A process kit according to claim32 wherein the sloped upper surface comprises an angle of between about85 to about 100°.